theodp writes: 'The lack of interest, the disdain for history is what makes computing not-quite-a-field,' Alan Kay once lamented. And so it should come as no surprise that the USPTO granted Google a patent Tuesday for the Automatic Deletion of Temporary Files, perhaps unaware that the search giant's claimed invention is essentially a somewhat kludgy variation on file expiration processing, a staple of circa-1970 IBM mainframe computing and subsequent disk management software. From Google's 2013 patent: 'A path name for a file system directory can be "C:temp\12-1-1999\" to indicate that files contained within the file system directory will expire on Dec. 1, 1999.' From Judith Rattenbury's 1971 Introduction to the IBM 360 computer and OS/JCL : 'EXPDT=70365 With this expiration date specified, the data set will not be scratched or overwritten without special operator action until the 365th day of 1970.' Hey, things are new if you've never seen them before!

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Expiry dates apply to tapes rather than disc files or directories, all tapes have an expiry date - even if it is "infinity".The border is rather fuzzy nowadays - modern tape libraries are actually virtual tapes [wikipedia.org] emulated on discs.

As you noted, tape files have been able to really be disk files for some time now and EXPDT still applies. Other decades-old disk management features such as MGMTCLAS provide a level of control over file management that's far beyond what's described in the Google patent.